An electronic device may have a display that provides image light to a waveguide. first and second liquid crystal lenses may be mounted to opposing surfaces of the waveguide. An coupler may couple the image light out of the waveguide through the first lens. The second lens may convey world light to the first lens. Control circuitry may control the first lens to apply a first optical power to the image light and the world light and may control the second lens to apply a second optical power to the world light that cancels out the first optical power. Each lens may include two layers of liquid crystal molecules having antiparallel pretilt angles. The pretilt angles and rubbing directions of the first lens may be antiparallel to corresponding pretilt angles and rubbing directions of the second lens about the waveguide.
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18. A display comprising:
a waveguide having opposing first and second sides, the waveguide being configured to propagate light via total internal reflection and comprising an output coupler;
a first liquid crystal layer at the first side; and
a second liquid crystal layer at the second side, wherein the first liquid crystal layer comprises first liquid crystal molecules having a first pretilt angle across a thickness of the first liquid crystal layer and the second liquid crystal layer comprises second liquid crystal molecules having a second pretilt angle, and wherein the output coupler is configured to couple the light propagated via total internal reflection out of the waveguide through the first liquid crystal layer.
1. An electronic device comprising:
a waveguide having opposing first and second surfaces;
a display configured to emit first light into the waveguide;
a first liquid crystal lens at the first surface and comprising a first liquid crystal layer having first liquid crystal molecules with a first pretilt angle across a thickness of the first liquid crystal layer;
a second liquid crystal lens at the second surface and comprising a second liquid crystal layer having second liquid crystal molecules with a second pretilt angle across a thickness of the second liquid crystal layer, the second pretilt angle being different from the first pretilt angle; and
an output coupler configured to couple the first light out of the waveguide through the first liquid crystal lens.
16. A display comprising:
pixels;
a waveguide configured to convey first light emitted by the pixels;
a first liquid crystal lens at a first side of the waveguide;
a second liquid crystal lens on the first liquid crystal lens;
a third liquid crystal lens at a second side of the waveguide; and
a fourth liquid crystal lens on the third liquid crystal lens, wherein the third and fourth liquid crystal lenses are configured to pass the first light and second light from the first and second liquid crystal lenses, the first liquid crystal lens has first antiparallel rubbing directions, the second liquid crystal lens has second antiparallel rubbing directions different from the first antiparallel rubbing directions, the third liquid crystal lens has third antiparallel rubbing directions aligned with the first antiparallel rubbing directions, and the fourth liquid crystal lens has fourth antiparallel rubbing directions aligned with the second antiparallel rubbing directions.
11. An optical system configured to convey first light from a display and second light, the optical system comprising:
a waveguide having opposing first and second surfaces;
a first transparent layer at the first surface;
a first liquid crystal layer mounted to the first transparent layer;
a second transparent layer mounted to the first liquid crystal layer, wherein the first and second transparent layers and the first liquid crystal layer are configured to pass the first light and the second light;
a third transparent layer at the second surface;
a second liquid crystal layer mounted to the third transparent layer; and
a fourth transparent layer mounted to the second liquid crystal layer, wherein the third and fourth transparent layers and the second liquid crystal layer are configured to pass the second light, wherein the first and third transparent layers have a first rubbing direction, and wherein the second and fourth transparent layers have a second rubbing direction different from the first rubbing direction.
2. The electronic device defined in
3. The electronic device defined in
4. The electronic device defined in
5. The electronic device defined in
6. The electronic device defined in
7. The electronic device defined in
a linear polarizer interposed between the first liquid crystal lens and the first surface of the waveguide.
8. The electronic device defined in
9. The electronic device defined in
a third liquid crystal lens mounted to the first liquid crystal lens and aligned with the first and second liquid crystal lenses; and
a fourth liquid crystal lens mounted to the second liquid crystal lens and aligned with the first, second, and third liquid crystal lenses, wherein the first and second liquid crystal lenses have first rubbing directions, and the third and fourth liquid crystal lenses have second rubbing directions orthogonal to the first rubbing directions.
10. The electronic device defined in
12. The optical system defined in
a fifth transparent layer mounted to the second transparent layer;
a third liquid crystal layer mounted to the fifth transparent layer; and
a sixth transparent layer mounted to the third liquid crystal layer, wherein the fifth transparent layer has the second rubbing direction and the sixth transparent layer has the first rubbing direction, and wherein the fifth and sixth transparent layers and the third liquid crystal layer are configured to pass the first light and the second light.
13. The optical system defined in
a seventh transparent layer mounted to the fourth transparent layer;
a fourth liquid crystal layer mounted to the seventh transparent layer; and
an eighth transparent layer mounted to the fourth liquid crystal layer, wherein the seventh transparent layer has the second rubbing direction and the eight transparent layer has the first rubbing direction, and wherein the seventh and eighth transparent layers and the fourth liquid crystal layer are configured to pass the second light.
14. The optical system defined in
first elongated electrodes and a first common electrode coupled to opposing sides of the first liquid crystal layer;
second elongated electrodes and a second common electrode coupled to opposing sides of the second liquid crystal layer, wherein the first elongated electrodes extend parallel to the second elongated electrodes;
third elongated electrodes and a third common electrode coupled to opposing sides of the third liquid crystal layer; and
fourth elongated electrodes and a fourth common electrode coupled to opposing sides of the fourth liquid crystal layer, wherein the third elongated electrodes extend parallel to the fourth elongated electrodes and orthogonal to the first and second elongated electrodes.
15. The optical system defined in
a linear polarizer interposed between the third transparent layer and the waveguide, wherein the linear polarizer has a transmission axis aligned with the first and second rubbing directions.
17. The display defined in
a first layer of liquid crystal molecules having a first pretilt angle; and
a second layer of liquid crystal molecules having a second pretilt angle different from the first pretilt angle.
19. The display of
20. The display of
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This application claims the benefit of provisional patent application No. 62/717,628, filed Aug. 10, 2018, which is hereby incorporated by reference herein in its entirety.
This relates generally to electronic devices and, more particularly, to electronic devices with displays.
Electronic devices with displays may be used to display content for a user. If care is not taken, the components used in displaying content for a user in an electronic device may be unsightly and bulky and may not exhibit desired levels of optical performance.
An electronic device may have a display that provides image light to a waveguide via an input coupler. The image light may propagate through the waveguide under the principle of total internal reflection. A first liquid crystal lens may be mounted to a first surface of the waveguide and a second liquid crystal lens may be mounted to a second surface of the waveguide. An output coupler may couple the image light out of the waveguide through the first liquid crystal lens. The second liquid crystal lens may convey world light from objects external to the electronic device to the first liquid crystal lens through the waveguide.
Control circuitry may control the first liquid crystal lens to exhibit a first index-of-refraction profile that applies a first optical power to the image light and the world light. The control circuitry may control the second liquid crystal lens to exhibit a second index-of-refraction profile that applies a second optical power to the world light that at least partially cancels out the first optical power. A linear polarizer may be interposed between the waveguide and the first liquid crystal lens to ensure the linear polarization aligns with the rubbing directions of the liquid crystal lenses. If desired, a third liquid crystal lens may be mounted to the first liquid crystal lens and a fourth liquid crystal lens may be mounted to the second liquid crystal lens. If the third and fourth liquid crystal lenses are employed, the linear polarizer may be omitted and both polarization states from the world light and the image light may be used.
The first and second liquid crystal lenses may include transparent substrates with aligned rubbing directions. Each liquid crystal lens may include two layers of liquid crystal molecules having antiparallel pretilt angles. The pretilt angles and rubbing directions of the first liquid crystal lens may be antiparallel to corresponding pretilt angles and rubbing directions of the second liquid crystal lens about the waveguide.
Electronic devices such as head-mounted devices and other devices may be used for augmented reality and virtual reality systems. These devices may include portable consumer electronics (e.g., portable electronic devices such as tablet computers, cellular telephones, glasses, other wearable equipment, etc.), head-up displays in cockpits, vehicles, etc., and display-based equipment (televisions, projectors, etc.). Devices such as these may include displays and other optical components. Device configurations in which virtual reality and/or augmented reality content is provided to a user with a head-mounted display device are described herein as an example. This is, however, merely illustrative. Any suitable equipment may be used in providing a user with virtual reality and/or augmented reality content.
A head-mounted device such as a pair of augmented reality glasses that is worn on the head of a user may be used to provide a user with computer-generated content that is overlaid on top of real-world content. The real-world content may be viewed directly by a user through a transparent portion of an optical system. The optical system may be used to route images from one or more pixel arrays or a scanning device in a display system to the eyes of a viewer. A waveguide such as a thin planar waveguide formed from one or more sheets of transparent material such as glass or plastic or other light guides may be included in the optical system to convey image light from the pixel arrays to the viewer.
The illumination system may include a light source that supplies illumination for the display. The illuminated display produces image light. An input optical coupler may be used to couple light from the light source into a waveguide in the illumination system. An output optical coupler may be used to couple display illumination out of the waveguide. Input and output couplers may also be used to couple image light from the display into a waveguide in the optical system and to couple the image light out of the waveguide for viewing by the viewer.
The input and output couplers for the head-mounted device may form structures such as Bragg gratings, prisms, angled transparent structures, and/or lenses that couple light into the waveguide and that couple light out of the waveguide. Input and output optical couplers may be formed from diffractive couplers such as volume holograms, other holographic coupling elements, or other diffractive coupling structures. The input and output couplers may, for example, be formed from thin or thick layers of photopolymers and/or other optical coupler structures in which holographic patterns are recorded using lasers. In some configurations, optical couplers may be formed from dynamically adjustable devices such as liquid crystal components (e.g., tunable liquid crystal gratings, polymer dispersed liquid crystal devices), or other adjustable optical couplers.
A schematic diagram of an illustrative head-mounted device is shown in
Head-mounted device 10 may include input-output circuitry 14. Input-output circuitry 14 may be used to allow data to be received by head-mounted display 10 from external equipment (e.g., a tethered computer, a portable device such as a handheld device or laptop computer, or other electrical equipment) and to allow a user to provide head-mounted device 10 with user input. Input-output circuitry 14 may also be used to gather information on the environment in which head-mounted device 10 is operating. Output components in circuitry 14 may allow head-mounted device 10 to provide a user with output and may be used to communicate with external electrical equipment.
As shown in
Optical components 16 may be used in forming the optical system that presents images to the user. Components 16 may include static components such as waveguides, static optical couplers, and fixed lenses. Components 16 may also include adjustable optical components such as an adjustable polarizer, tunable lenses (e.g., liquid crystal tunable lenses, tunable lenses based on electrooptic materials, tunable liquid lenses, microelectromechanical systems (MEMS) tunable lenses, or other tunable lenses), a dynamically adjustable coupler (e.g., an adjustable MEMs grating or other coupler), an adjustable liquid crystal holographic coupler such as an adjustable liquid crystal Bragg grating coupler, adjustable holographic couplers (e.g., electro-optical devices such as tunable Bragg grating couplers, polymer dispersed liquid crystal devices), couplers, lenses, and other optical devices formed from electro-optical materials (e.g., lithium niobate or other materials exhibiting the electro-optic effect), or other static and/or tunable optical components. Components 16 may be used in providing light to display(s) 18 to illuminate display(s) 18 and may be used in providing images from display(s) 18 to a user for viewing. In some configurations, one or more of components 16 may be stacked, so that light passes through multiple components in series. In other configurations, components may be spread out laterally (e.g., multiple displays may be arranged on a waveguide or set of waveguides using a tiled set of laterally adjacent couplers). Configurations may also be used in which both tiling and stacking are present.
Input-output circuitry 14 may include components such as input-output devices 22 for gathering data and user input and for supplying a user with output. Devices 22 may include sensors 26, audio components 24, and other components for gathering input from a user or the environment surrounding device 10 and for providing output to a user. Devices 22 may, for example, include keyboards, buttons, joysticks, touch sensors for trackpads and other touch sensitive input devices, cameras, light-emitting diodes, and/or other input-output components.
Cameras in input-output devices 22 may gather images of the user's eyes and/or the environment surrounding the user. As an example, eye-facing cameras may be used by control circuitry 12 to gather images of the pupils and other portions of the eyes of the viewer. The locations of the viewer's pupils and the locations of the viewer's pupils relative to the rest of the viewer's eyes may be used to determine the locations of the centers of the viewer's eyes (i.e., the centers of the user's pupils) and the direction of view (gaze direction) of the viewer's eyes.
Sensors 26 may include position and motion sensors (e.g., compasses, gyroscopes, accelerometers, and/or other devices for monitoring the location, orientation, and movement of head-mounted display 10, satellite navigation system circuitry such as Global Positioning System circuitry for monitoring user location, etc.). Using sensors 26, for example, control circuitry 12 can monitor the current direction in which a user's head is oriented relative to the surrounding environment. Movements of the user's head (e.g., motion to the left and/or right to track on-screen objects and/or to view additional real-world objects) may also be monitored using sensors 26.
If desired, sensors 26 may include ambient light sensors that measure ambient light intensity and/or ambient light color, force sensors, temperature sensors, touch sensors, capacitive proximity sensors, light-based proximity sensors, other proximity sensors, strain gauges, gas sensors, pressure sensors, moisture sensors, magnetic sensors, etc. Audio components 24 may include microphones for gathering voice commands and other audio input and speakers for providing audio output (e.g., ear buds, bone conduction speakers, or other speakers for providing sound to the left and right ears of a user). If desired, input-output devices 22 may include haptic output devices (e.g., vibrating components), light-emitting diodes and other light sources, and other output components. Circuitry 14 may include wired and wireless communications circuitry 20 that allows head-mounted display 10 (e.g., control circuitry 12) to communicate with external equipment (e.g., remote controls, joysticks and other input controllers, portable electronic devices, computers, displays, etc.) and that allows signals to be conveyed between components (circuitry) at different locations in head-mounted display 10.
The components of head-mounted display 10 may be supported by a head-mountable support structure such as illustrative support structure 28 of
Optical system 33 may be supported within support structure 28 and may be used to provide images from display(s) 18 to a user (see, e.g., the eyes of user 42 of
As shown in
Output coupler 52 (e.g., at end 58 of waveguide 48) couples light 54 (image light) out of waveguide 48 and towards viewer 42 (an eye of a user), as output light (output image light) 76. Input coupler 50 and output coupler 52 may, for example, include structures such as Bragg gratings or other diffraction gratings that couple light into waveguides and that couple light out of the waveguides. Couplers 50 and 52 may be formed from volume holograms or other holographic coupling elements (e.g., thin layers of polymers and/or other optical coupler structures in which holographic patterns are recorded using lasers), prisms, angled transparent structures, lenses, or any other desired light coupling elements. Couplers 50 and 52 may have infinite focal lengths (e.g., couplers 50 and 52 may be plane-to-plane couplers) or may have associated finite focal lengths. Couplers 50 and/or 52 may be embedded within waveguide 48, formed on surface 62 of waveguide 48, and/or formed on surface 64 of waveguide 48.
Light 80 from external objects such as object 36 may pass through waveguide 48 (e.g., at end 58 of waveguide 48, within central region 34 of
One or more lenses may be used to direct output image light 76 towards eye box 78 with desired optical characteristics (e.g., with a desired optical power, focal length, image depth, etc.). It may be desirable to be able to adjust these optical characteristics over time (e.g., based on changes in sensor data gathered using sensors 26 of
Adjustable lens components 66 and 68, which may sometimes be referred to as adjustable lenses, adjustable lens systems, adjustable optical systems, adjustable lens devices, tunable lenses, etc., may contain electrically adjustable material such as liquid crystal material, volume Bragg gratings, or other electrically modulated material that may be adjusted to produce customized lenses. Each of components 66 and 68 may contain an array of electrodes that apply electric fields to portions of a layer of liquid crystal material or other voltage-modulated optical material with an electrically adjustable index of refraction (sometimes referred to as an adjustable lens power or adjustable phase profile). By adjusting the voltages of signals applied to the electrodes, the index of refraction profile of components 66 and 68 may be dynamically adjusted. This allows the size, shape, and location of the lenses formed within components 66 and 68 to be adjusted. An example in which adjustable lens components 66 and 68 are formed from layers of liquid crystal material is described herein as an example. Adjustable lens components 66 and 68 may therefore be referred to herein as liquid crystal lenses 66 and 68.
Control circuitry 12 may adjust liquid crystal lens 68 in real time to modulate output image light 76 with different desired optical characteristics over time (e.g., optical power, image depth, etc.). In general, it may be desirable to modulate output image light 76 without also modulating world light 80 (e.g., to adjust the optical characteristics of output image light 76 without also adjusting those optical characteristics of world light 80).
World light 80 passes through liquid crystal lens 66 prior to passing through waveguide 48. Control circuitry 12 may control liquid crystal lens 66 to exhibit an index of refraction profile that is the opposite (reverse) of the index of refraction profile provided by liquid crystal lens 66 (e.g., so that the optical power provided by liquid crystal lens 66 to world light 80 cancels out the optical power provided by liquid crystal lens 68 to world light 80). In this way, output image light 76 may be modulated by liquid crystal lens 68 whereas any modulation by liquid crystal lens 68 on world light 80 is canceled out by modulation from liquid crystal lens 66 (e.g., control circuitry 12 may modulate output image light 76 from display(s) 18 without modulating world light 80 from external object 36).
If desired, device 10 may include additional lenses such as lenses 74 and 72. As shown in
In some scenarios, it may be desirable to provide output image light 76 with a particular linear polarization. In one arrangement, a first linear polarizer is interposed between display(s) 18 and input coupler 50 for providing image light 44 with a first linear polarization and a second linear polarizer is interposed between lens 74 and waveguide 48 for providing world light 80 with a second linear polarization. However, in practice, linearly-polarized light does not maintain its linear polarization state as it propagates down the length of waveguide 48 from end 56 to output coupler 52 (e.g., due to phase shifts generated at each reflection off at surfaces 62 and 64 of waveguide 48). This may lead to undesirable artifacts such as double images from display(s) 18.
In order to maintain the linear polarization state of output image light 76 by the time the light reaches liquid crystal lens 68, a linear polarizer such as linear polarizer 70 may be interposed between surface 64 of waveguide 48 and liquid crystal lens 68. This allows light 54 to retain its polarization before passing through liquid crystal lens 68. Linear polarizer 70 also serves to linearly polarize world light 80. In the example of
Liquid crystal lens 66 and liquid crystal lens 68 may each include a respective pair of liquid crystal cells. Each liquid crystal cell may include a corresponding layer of liquid crystal molecules. The pretilt angle of the liquid crystal molecules in the first liquid crystal cell of liquid crystal lens 66 may be opposite to the pretilt angle of the liquid crystal molecules in the second liquid crystal cell of liquid crystal lens 66. Similarly, the pretilt angle of the liquid crystal molecules in the first liquid crystal cell of lens 68 may be opposite to the pretilt angle of the liquid crystal molecules in the second liquid crystal cell of lens 68.
The pretilt angles of the liquid crystal molecules can be set by providing substrates within liquid crystal lenses 66 and 68 with particular rubbing directions (e.g., the liquid crystal molecules may contact the substrates and align along the corresponding rubbing directions). In the example of
The example of
In order to mitigate these effects, the pretilt angles of the liquid crystal molecules in liquid crystal lens 66 may be opposite to the corresponding pretilt angles in liquid crystal lens 68 (e.g., with respect to waveguide 48).
As shown in
Liquid crystal cell 90 may have patterns of electrodes such as electrode layers 108 and 112 that can be supplied with signals from control circuitry 12 to produce desired voltages on liquid crystal cell 90. Electrode layer 108 may be patterned on substrate 106 whereas electrode layer 112 may be patterned on substrate 114. In one suitable arrangement, electrode layer 108 may include a common electrode (e.g., a blanket or plane of conductive material on substrate 106) whereas electrode layer 112 includes elongated electrodes (e.g., strip-shaped electrodes or finger electrodes) on substrate 114. The strip-shaped electrodes may extend parallel to the X-axis of
At each location of the vertical electrodes 112, a desired voltage may be applied across liquid crystal layer 110 by supplying a first voltage to electrodes 112 and a second voltage (e.g., a ground voltage) to common electrode 108. The liquid crystal between the two electrode layers will receive an applied electric field with a magnitude that is proportional to the difference between the first and second voltages on the electrode layers. By controlling the voltages on electrodes 112 and 108, the index of refraction of liquid crystal layer 110 of liquid crystal cell 90 can be dynamically adjusted to produce customized lenses.
When an electric field is applied to the liquid crystals of layer 110, the liquid crystals change orientation. The speed at which a given liquid crystal material can be reoriented is limited by factors such as the thickness of layer 110. To increase the tuning speed of liquid crystal layer 110 while still achieving a suitable tuning range, liquid crystal lens 66 may include two or more liquid crystal cells stacked on top of one another. This type of arrangement is illustrated in
As shown in
Substrates 116 and 124 may be formed from clear glass, sapphire or other transparent crystalline material, transparent plastic, thin coatings or films, other transparent layers, and/or combinations of these. Liquid crystal cell 92 may have patterns of electrodes such as electrode layers 118 and 122 that can be supplied with signals from control circuitry 12 to produce desired voltages on liquid crystal cell 92. Electrode layer 118 may be patterned on substrate 116 whereas electrode layer 122 may be patterned on substrate 124. In one suitable arrangement, electrode layer 122 may include a common electrode (e.g., a blanket or plane of conductive material on substrate 124) whereas electrode layer 118 includes elongated electrodes (e.g., strip-shaped electrodes or finger electrodes) on substrate 116. The strip-shaped electrodes may extend parallel to the Y-axis of
At each location of the horizontal electrodes 118, a desired voltage may be applied across liquid crystal layer 120 by supplying a first voltage to electrodes 118 and a second voltage (e.g., a ground voltage) to common electrode 122. The liquid crystal between the two electrode layers will receive an applied electric field with a magnitude that is proportional to the difference between the first and second voltages on the electrodes. By controlling the voltages on electrodes 118 and 124, the index of refraction of liquid crystal layer 120 of liquid crystal cell 92 can be dynamically adjusted to produce customized lenses.
If desired, the rubbing direction and pretilt angles of liquid crystal cells 90 and 92 in lens 66 may be antiparallel with respect to each other. In particular, liquid crystal molecules 126A of upper liquid crystal cell 90 may have a first pretilt angle and liquid crystal molecules 126B of lower liquid crystal cell 92 may have a second pretilt angle that is opposite to the first pretilt angle (e.g., the optical axis of liquid crystal molecules 126B may be oriented at a positive angle with respect to the Z-axis of
In order to obtain these opposing pretilt angles, the upper substrate of each liquid crystal cell may be formed using opposite (antiparallel) rubbing directions and the lower substrate of each liquid crystal cell may be formed using opposite (antiparallel) rubbing directions. As shown in
Overlapping portions of liquid crystal layers 110 and 120 in lens 66 may be controlled using the same or different voltages to achieve the desired index of refraction at that portion of lens 66. For example, a first voltage V1 may be applied across a given portion of upper liquid crystal layer 110 whereas a second voltage V2 may be applied across that portion of lower liquid crystal layer 120. Voltages V1 and V2 may be different or may be the same. Control circuitry 12 may determine the magnitudes and ratio of V1 to V2 based on the desired index of refraction at that portion of the liquid crystal lens 66 (e.g., to provide lens 66 with an opposite optical power to lens 68).
Surface 100 of substrate 124 may be mounted to surface 62 of waveguide 48 of
As shown in
Liquid crystal cell 94 may have patterns of electrodes such as electrode layers 130 and 134 that can be supplied with signals from control circuitry 12 to produce desired voltages on liquid crystal cell 94. Electrode layer 130 may be patterned on substrate 128 whereas electrode layer 134 may be patterned on substrate 136. In one suitable arrangement, electrode layer 130 may include a common electrode (e.g., a blanket or plane of conductive material on substrate 128) whereas electrode layer 134 includes elongated electrodes (e.g., strip-shaped electrodes or finger electrodes) on substrate 136. The strip-shaped electrodes may extend parallel to the Y-axis of
At each location of the horizontal electrodes 134, a desired voltage may be applied across liquid crystal layer 132 by supplying a first voltage to electrodes 134 and a second voltage (e.g., a ground voltage) to common electrode 130. The liquid crystal between the two electrode layers will receive an applied electric field with a magnitude that is proportional to the difference between the first and second voltages on the electrodes. By controlling the voltages on electrodes 130 and 134, the index of refraction of liquid crystal layer 132 of liquid crystal cell 94 can be dynamically adjusted to produce customized lenses.
As shown in
Substrates 138 and 146 may be formed from clear glass, sapphire or other transparent crystalline material, transparent plastic, thin coatings or films, other transparent layers, and/or combinations of these. Liquid crystal cell 96 may have patterns of electrodes such as electrode layers 140 and 144 that can be supplied with signals from control circuitry 12 to produce desired voltages on liquid crystal cell 96. Electrode layer 140 may be patterned on substrate 138 whereas electrode layer 144 may be patterned on substrate 146. In one suitable arrangement, electrode layer 144 may include a common electrode (e.g., a blanket or plane of conductive material on substrate 146) whereas electrode layer 140 includes elongated electrodes (e.g., strip-shaped electrodes or finger electrodes) on substrate 138. The strip-shaped electrodes may extend parallel to the X-axis of
At each location of the vertical electrodes 140, a desired voltage may be applied across liquid crystal layer 142 by supplying a first voltage to electrodes 140 and a second voltage (e.g., a ground voltage) to common electrode 144. The liquid crystal between the two electrode layers will receive an applied electric field with a magnitude that is proportional to the difference between the first and second voltages on the electrodes. By controlling the voltages on electrodes 140 and 144, the index of refraction of liquid crystal layer 142 of liquid crystal cell 96 can be dynamically adjusted to produce customized lenses.
If desired, the rubbing direction and pretilt angles of liquid crystal cells 94 and 96 in lens 68 may be antiparallel or opposite with respect to each other. In particular, liquid crystal molecules 148A of upper liquid crystal cell 94 may have a first pretilt angle and liquid crystal molecules 148B of lower liquid crystal cell 96 may have a second pretilt angle that is opposite to the first pretilt angle (e.g., the optical axis of liquid crystal molecules 148B may be oriented at a positive angle with respect to the Z-axis of
In order to obtain these opposing pretilt angles, the upper substrate of each liquid crystal cell may be formed using opposite rubbing directions and the lower substrate of each liquid crystal cell may be formed using opposite rubbing directions. As shown in
In this way, the rubbing direction of substrate 106 of lens 66 may be parallel to the rubbing direction of substrate 124 of lens 66 and substrates 128 and 146 of lens 68. Similarly, the rubbing direction of substrate 106 of lens 66 may be antiparallel to the rubbing direction of substrates 114 and 116 of lens 66 and substrates 136 and 138 of lens 68. In addition, the pretilt angle of liquid crystal molecules 126B in lens 66 may be opposite to the pretilt angle of liquid crystal molecules 148A. Similarly, the pretilt angle of liquid crystal molecules 126A in lens 66 may be opposite to the pretilt angle of liquid crystal molecules 148B. In other words, the pretilt angles of liquid crystal lens 66 may be opposite to the corresponding pretilt angles of liquid crystal lens 68 about waveguide 48.
Overlapping portions of liquid crystal layers 132 and 142 in lens 68 may be controlled using the same or different voltages to achieve the desired index of refraction at that portion of lens 68. For example, a first voltage V3 may be applied across a given portion of upper liquid crystal layer 132 whereas a second voltage V4 may be applied across that portion of lower liquid crystal layer 142. Voltages V3 and V4 may be different or may be the same. Control circuitry 12 may determine the ratio of V3 to V4 based on the desired index of refraction at that portion of the liquid crystal lens 66 (e.g., based on the disposition of the user's eyes 16). This may serve to configure lens 68 to provide output image light 76 (
The example of
Curve 168 plots an exemplary refractive index n generated for liquid crystal lens 68. As shown by curve 168, refractive index n has been varied inversely to the refractive index associated with curve 166 (e.g., refractive index n for lens 66 may be relatively low at locations where refractive index n for lens 68 is relatively high and refractive index n for lens 66 may be relatively high at locations where refractive index n for lens 68 is relatively low). This may, for example, provide liquid crystal lens 68 with an optical power opposite to the optical power of liquid lens 66. In this way, the optical power of lens 68 may cancel out the optical power applied to world light 80 (
In the example of
In the example of
In the example of
As shown in
Liquid crystal lenses 174 and 176 may be used to provide output image light 76 with desired optical power. Liquid crystal lenses 170 and 172 may be used to cancel out the optical power provided to world light 80 by lenses 174 and 176 (e.g., so that world light 80 is not modulated by the time it reaches eye box 78). For example, control circuitry 12 may control liquid crystal lens 172 to cancel out the optical power provided by liquid crystal lens 174 (e.g., by providing lens 172 with an inverse index-of-refraction profile relative to that provided to lens 174). Similarly, control circuitry 12 may control liquid crystal lens 170 to cancel out the optical power provided by liquid crystal lens 176 (e.g., by providing lens 170 with an inverse index-of-refraction profile relative to that provided to lens 176).
The pretilt angles of the liquid crystal molecules and the rubbing directions of the substrates in lenses 170 and 176 may extend along orthogonal directions relative to the pretilt angles of the liquid crystal molecules and the rubbing directions of the substrates in lenses 172 and 174. For example, the rubbing directions in lens 172 may extend parallel to the Y-axis of
The example of
Liquid crystal cell 188 of liquid crystal lens 172 may be stacked under liquid crystal cell 186. Liquid crystal cell 188 may include liquid crystal layer 210. Liquid crystal layer 210 may be interposed between transparent substrates such as upper substrate 208 and lower substrate 212. The electrode layers of lenses 172 and 174 have been omitted from
The rubbing directions and pretilt angle of liquid crystal cell 186 may be antiparallel to the rubbing directions and pretilt angle of liquid crystal cell 188. In particular, liquid crystal molecules 214A of upper liquid crystal cell 186 may have a first pretilt angle and liquid crystal molecules 214B of lower liquid crystal cell 188 may have a second pretilt angle that is opposite to the first pretilt angle. Similarly, the upper substrate of each liquid crystal cell in lens 172 may be formed using opposite rubbing directions and the lower substrate of each liquid crystal cell may be formed using opposite rubbing directions.
As shown in
Surface 196 of substrate 212 may be mounted to surface 62 of waveguide 48 of
As shown in
The rubbing directions and pretilt angle of liquid crystal cell 190 may be antiparallel or opposite to the rubbing directions and pretilt angle of liquid crystal cell 192. In particular, liquid crystal molecules 236A of upper liquid crystal cell 190 may have a first pretilt angle and liquid crystal molecules 236B of lower liquid crystal cell 192 may have a second pretilt angle that is opposite to the first pretilt angle. Similarly, the upper substrate of each liquid crystal cell in lens 174 may be formed using opposite rubbing directions and the lower substrate of each liquid crystal cell may be formed using opposite rubbing directions.
As shown in
In this way, the rubbing direction of substrate 202 of lens 172 may be parallel to the rubbing direction of substrate 212 of lens 172 and substrates 224 and 234 of lens 174. Similarly, the rubbing direction of substrate 202 of lens 172 may be antiparallel to the rubbing direction of substrates 206 and 208 of lens 172 and substrates 228 and 230 of lens 174. In addition, the pretilt angle of liquid crystal molecules 214B in lens 172 may be opposite to the pretilt angle of liquid crystal molecules 236A. Similarly, the pretilt angle of liquid crystal molecules 214A in lens 66 may be opposite to the pretilt angle of liquid crystal molecules 236B. In other words, the pretilt angles of liquid crystal lens 172 may be opposite to the corresponding pretilt angles of liquid crystal lens 174 about waveguide 48 (e.g., as long as the liquid crystal cells have the same electrode directions).
The example of
Liquid crystal cell 248 of liquid crystal lens 170 may be stacked under liquid crystal cell 246. Liquid crystal cell 248 may include liquid crystal layer 270. Liquid crystal layer 270 may be interposed between transparent substrates such as upper substrate 268 and lower substrate 272. The electrode layers of lenses 170 and 176 have been omitted from
The rubbing directions and pretilt angle of liquid crystal cell 246 may be antiparallel to the rubbing directions and pretilt angle of liquid crystal cell 248. In particular, liquid crystal molecules 274A of upper liquid crystal cell 246 may have a first pretilt angle and liquid crystal molecules 274B of lower liquid crystal cell 248 may have a second pretilt angle that is opposite to the first pretilt angle (e.g., orthogonal to the pretilt angles of liquid crystal molecules 214A, 214B, 236A, and 236B of
As shown in
Surface 256 of substrate 272 may be mounted to surface 194 of lens 172 (
As shown in
The rubbing directions and pretilt angle of liquid crystal cell 250 may be antiparallel or opposite to the rubbing directions and pretilt angle of liquid crystal cell 252. In particular, liquid crystal molecules 296A of upper liquid crystal cell 250 may have a first pretilt angle and liquid crystal molecules 296B of lower liquid crystal cell 252 may have a second pretilt angle that is opposite to the first pretilt angle. Similarly, the upper substrate of each liquid crystal cell in lens 176 may be formed using opposite rubbing directions and the lower substrate of each liquid crystal cell may be formed using opposite rubbing directions.
As shown in
In this way, the rubbing direction of substrate 262 of lens 170 may be parallel to the rubbing direction of substrate 272 of lens 170 and substrates 284 and 294 of lens 176. Similarly, the rubbing direction of substrate 262 of lens 170 may be antiparallel to the rubbing direction of substrates 266 and 268 of lens 170 and substrates 288 and 290 of lens 176. In addition, the pretilt angle of liquid crystal molecules 274B in lens 170 may be opposite to the pretilt angle of liquid crystal molecules 296A. Similarly, the pretilt angle of liquid crystal molecules 274A in lens 170 may be opposite to the pretilt angle of liquid crystal molecules 296B. In other words, the pretilt angles of liquid crystal lens 170 may be opposite to the corresponding pretilt angles of liquid crystal lens 176 about waveguide 48.
The example of
In general, lenses 170, 172, 174, and 176 of
Substrates 202, 206, 208, 212, 224, 228, 230, and 234 of
Electrode layers 108, 112, 118, 122, 130, 134, 140, and 144 of
The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.
Yan, Jin, Dorjgotov, Enkhamgalan, Aieta, Francesco, Yang, Young Cheol, Oh, Se Baek, Stamenov, Igor, DeLapp, Scott M., Steele, Bradley C.
Patent | Priority | Assignee | Title |
Patent | Priority | Assignee | Title |
10168540, | Dec 22 2010 | SEEREAL TECHNOLOGIES S.A. | Combined light modulation device for tracking users |
10609363, | Feb 16 2017 | CITIBANK, N A | Method and system for display device with integrated polarizer |
8508830, | May 13 2011 | GOOGLE LLC | Quantum dot near-to-eye display |
8599301, | Apr 17 2006 | OmniVision Technologies, Inc | Arrayed imaging systems having improved alignment and associated methods |
9927614, | Dec 29 2015 | Microsoft Technology Licensing, LLC | Augmented reality display system with variable focus |
20070008617, | |||
20110221656, | |||
20180146188, | |||
20190227375, | |||
20190377181, | |||
CN101023392, | |||
CN103399445, | |||
CN107422570, | |||
CN1264842, | |||
CN1871545, | |||
WO2017176898, |
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